Singular of corpora

[sarathkcm]

Singular of corpora gives corpora, but it should give corpus. Plural of corpora gives corporas, but it should be corpora as it is already plural.

Plural of corpus currently gives corpuses, which is correct, but it can be corpora too. Adding an irregularRule to pluralize corpus into corpora will fix both the above issues, and will have no problem converting corpuses into corpus when singularized.
Tested here: https://runkit.com/embed/jmts2xe7kj1b

Thoughts? Can this irregular rule be added by default? I can raise a pull if needed.